Tracey Russell has several reasons to consider herself lucky, but one stands out. Around December 14 2006, after the bodies of five of her fellow sex workers had been found but before anyone had been arrested, she agreed to have sex with their killer.

Tracey and her best friend Annette Nicholls had agreed, after the first women went missing, only to go with regulars, but Steve Wright was someone they both knew well; Tracey had had sex with him several times in the three years he had been using Ipswich prostitutes - not a matter of weeks, as he testified in court.

On that occasion, however, she did not. Having gone back to his flat at 79 London Road and agreed the fee, she had prepared to have sex on his bed, but they were disturbed by a bang on the door or from a car outside, and he told her to get out.

Tracey, who is 31, spoke to the Guardian in December under a pseudonym, but as the end of the trial approached she agreed to speak more openly about Annette and the four other women, all of whom she knew, and about the man who killed them. The women knew Wright as just another punter, she said. "Annette went with him a couple of times, I knew that, I did, and I know a few of the other girls did.

"We were worried, but when you are on drugs, you think if you can open a car door ... you would know that it was the murderer. Me and Annette said don't get in cars with anyone we don't know, just get in cars with regulars, and that's what we did. But it was a regular that ended up being the [killer].

"He was always a late person to come out, he would drive round a couple of times, then choose the girl he wanted. We used to call them 'window-lickers' if they went around a lot. He was one of them. We didn't suspect him."

Annette, she says, had worked only infrequently until a few months before her death, when her heroin and crack addiction became more desperate. "She just got more depressed and the crack got hold of her."

Their life, she said, was "horrible". "You learn to blank it out over the years, and because you are on drugs, [you] just think of something else. I know that sounds odd, but you do. 'Cos you get used to it, and it's over within seconds. Hopefully."

Shortly after Annette was confirmed dead, and with the help of a methadone prescription, Tracey stopped selling sex and using heroin, after six years on the game.

She is not alone. Of the 30 sex workers who were known to be working the Ipswich beat before the murders - some regulars, some working more erratically - only two are still working. Of the rest, 16 are in daily contact with drugs workers, seven needing less immediate support.

For the past 14 months the quiet success of those working to help women off the streets of Ipswich has continued.

Brian Tobin, director of Iceni, the small drugs charity that has spearheaded the effort, working with all the sex workers in Ipswich, describes the set of circumstances in the town as "pretty unique", acknowledging that the killings themselves - one sixth of the town's prostitutes were murdered - were critical in persuading the women and the relevant agencies to work together.

"We have to recognise that prior to the murders there were scant resources put into this area. I have worked in drugs for 16 years and I think [sex workers] are the most difficult and damaged clientele I have ever worked with. That needs resources."

All the same, the women have been helped into new circumstances with a relatively small amount of money - less than £30,000 in grants and donations, which the centre has used to meet their daily bills.

The support of Suffolk police in arresting kerb crawlers and supporting the women, and of Ipswich borough council in part-funding a sex liaison officer has also been key.

"It ain't rocket science," says Tobin. "We phone them every day. If a woman goes missing for 24 hours we keep on the case until we find them. I think for the first time in their lives someone genuinely cares for them, because they certainly don't."

He sees no reason why Ipswich's success couldn't be replicated elsewhere, though resources, and intense effort, are critical.

"Our hardest part is yet to come. Now we have got to sustain this. We are now getting to the root of the problem, which was hidden by drugs."

For Tracey, clean for a year, the conclusion of the trial is a relief. "Because I was on drugs at the time, you don't feel a lot, but now that I'm off the drugs and I'm on the methadone, everything's coming at once. It's a bit hard to ... you know. It's all been quick, what's happened. So I haven't really had time to grieve over her. It's hard."

As for escaping Wright, she says: "I feel like my life's been saved in a way, because it could have been me that's dead now. It makes me feel a bit of relief, but guilty, because I got away. I feel a little bit guilty because Annette's dead, and I got away."